X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=include%2Flttng%2Fringbuffer-config.h;h=c95d35cb348d820e69adba599ad3f90b9583b130;hb=82cd0cfd74e2e7fe71d9ff68a9e521d989f72d99;hp=87344c94c8285f94b296f318ae58880dedcc7a39;hpb=a9ff648cc4cc06d28b522d705c467d45ab916a9d;p=lttng-ust.git

diff --git a/include/lttng/ringbuffer-config.h b/include/lttng/ringbuffer-config.h
index 87344c94..c95d35cb 100644
--- a/include/lttng/ringbuffer-config.h
+++ b/include/lttng/ringbuffer-config.h
@@ -228,7 +228,7 @@ struct lttng_ust_lib_ring_buffer_config {
  * removed.
  */
 #define LTTNG_UST_RING_BUFFER_CTX_PADDING	\
-		(24 - sizeof(int) - sizeof(void *))
+		(24 - sizeof(int) - sizeof(void *) - sizeof(void *))
 struct lttng_ust_lib_ring_buffer_ctx {
 	/* input received by lib_ring_buffer_reserve(), saved here. */
 	struct channel *chan;		/* channel */
@@ -256,9 +256,21 @@ struct lttng_ust_lib_ring_buffer_ctx {
 					 */
 	uint64_t tsc;			/* time-stamp counter value */
 	unsigned int rflags;		/* reservation flags */
-	unsigned int padding1;		/* padding to realign on pointer */
+	/*
+	 * The field ctx_len is the length of struct
+	 * lttng_ust_lib_ring_buffer_ctx as known by the user of
+	 * lib_ring_buffer_ctx_init.
+	 */
+	unsigned int ctx_len;
 	void *ip;			/* caller ip address */
+	void *priv2;			/* 2nd priv data */
 	char padding2[LTTNG_UST_RING_BUFFER_CTX_PADDING];
+	/*
+	 * This is the end of the initial fields expected by the original ABI
+	 * between probes and UST. Only the fields above can be used if
+	 * ctx_len is 0. Use the value of ctx_len to find out which of the
+	 * following fields may be used.
+	 */
 };
 
 /**
@@ -274,12 +286,14 @@ static inline lttng_ust_notrace
 void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 			      struct channel *chan, void *priv,
 			      size_t data_size, int largest_align,
-			      int cpu, struct lttng_ust_shm_handle *handle);
+			      int cpu, struct lttng_ust_shm_handle *handle,
+			      void *priv2);
 static inline
 void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 			      struct channel *chan, void *priv,
 			      size_t data_size, int largest_align,
-			      int cpu, struct lttng_ust_shm_handle *handle)
+			      int cpu, struct lttng_ust_shm_handle *handle,
+			      void *priv2)
 {
 	ctx->chan = chan;
 	ctx->priv = priv;
@@ -288,8 +302,9 @@ void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 	ctx->cpu = cpu;
 	ctx->rflags = 0;
 	ctx->handle = handle;
-	ctx->padding1 = 0;
+	ctx->ctx_len = sizeof(struct lttng_ust_lib_ring_buffer_ctx);
 	ctx->ip = 0;
+	ctx->priv2 = priv2;
 	memset(ctx->padding2, 0, LTTNG_UST_RING_BUFFER_CTX_PADDING);
 }